Casting sleeve with williams core

ABSTRACT

A sleeve ( 110 ) for use in metal casting has a sleeve body, where a longitudinal axis (B) has a side wall ( 116 ) formed around it, defining a sleeve interior. The sleeve body is open at a first end ( 118 ). A core ( 120 ) is formed integrally along an interior surface extends into the sleeve interior. The sleeve body and the core are formed of a gas-permeable refractory material. At least the core contains material for generating heat when heated by a molten metal. The core extends along the side wall from the first end to a second end. The core has a width that is constant or decreases in a radial direction away from the side wall, especially with a triangular profile, with a base thereof in contact with the side wall. The sleeve body is cylindrical or frustoconical, with a diameter that decreases from the open first end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority as a bypass continuation of PCTapplication PCT/US2015/030714, filed on 14 May 2015, which in turnclaims priority to U.S. provisional patent application 61/993,147, filedon 14 May 2014. Both cited applications are incorporated by reference asif fully recited herein.

TECHNICAL FIELD

The disclosed embodiments of the present invention relate to sleevesused in the casting of metals. More specifically, the present inventionrelates to a sleeve that has a “Williams” core provided on an insidelength of the sleeve.

BACKGROUND OF THE ART

The so-called “Williams” core owes its name to the work in the 1930's ofJohn Williams of Palmyra, N.Y., as described in U.S. Pat. No. 2,205,327.While that patent speaks for itself and need not be described in anydetail here, the core now attributed to Williams is useful to provide ahot spot inside a sleeve used in metal casting. In some circles of theart, the Williams core is referred to as a “firecracker” core.

Sleeves are used in metal casting to provide a reservoir of molten metalduring the casting process. As molten metal pours into a mold cavity andsolidifies, it shrinks. The failure to replace this metal would resultin an undersized piece. Depending upon the size of the piece being cast,it may be necessary to place one or more sleeves in fluid communicationwith the cavity so that the shrinkage is obviated by the gravity flow ofthe molten metal in the sleeve into the cavity. In general, a sleevecomprises a material that allows the reservoir of molten metal formedduring the pour to remain molten longer than the molten metal enteringthe mold cavity, so that it is available for flow when needed.

In many instances, the sleeve has a top that is open to the atmosphere.By doing this, the gravity flow into the mold cavity is not opposed by avacuum being formed at the opposite end of the sleeve. However, this canallow undesired heat loss from the reservoir. This type of a sleeve isoften called an “open feeder.”

Also, there are circumstances, especially with a large pour, where thereservoir needs to be positioned low in the mold. In such a case, thereservoir is positioned entirely within the interior of the mold andthere is no way provided by the sleeve to counter the vacuum generatedby metal flow. These reservoirs are generally referred to as “blindheads.”

In his patent, Williams describes his core as a cylinder or rod of apreferably gas-permeable refractory material that allows communicationof the interior of a blind head with the surrounding sand, which is, ofcourse, gas-permeable. In this way, atmospheric pressure is providedinto the blind head, and particularly to the interior.

Over time, the Williams core has been refined so that U.S. Pat. No.4,467,858 to Trinkl says that the Williams core is typically in theshape of a cone or pyramid, with the pointed end extending into theinterior of the reservoir. Notably, Trinkl teaches several problemsencountered in producing Williams cores integrally with the sleeve orblind head. Even in the invention taught by Trinkl, the Williams coreextends inwardly from the cover at the top of the blind feeder sleeve.

Both Williams and Trinkl teach a sleeve that is placed in the mold sothat a generally longitudinal axis of the sleeve is aligned verticallyin use, with the Williams core at the top.

In some applications, there is a need to allow a sleeve to have itslongitudinal axis aligned horizontally when inserted into a mold. Onesuch situation is when the vertical green sand molding technology ofDISA Industries (Taalstrup, DK) is being used. These machines use avertically-split mold and the sleeves are necessarily inserted on theirside. One embodiment of such a machine is sold under the registeredtrademark DISAMATIC. The machine is an automatic production line forfast manufacturing. The need to place the sleeve on its side can arisefrom a requirement that the sleeve needs to be located at the section ofthe casting that will be the last to solidify.

It is therefore an unmet advantage of the prior art to provide a castingsleeve having a Williams core that can be effectively used in ahorizontal alignment.

SUMMARY OF THE INVENTION

This and other unmet advantages are provided by a sleeve for use inmetal casting. The sleeve comprises a sleeve body having a longitudinalaxis around which is formed a side wall that defines an interior of thesleeve. The sleeve body is open at a first end thereof. A core is formedintegrally along an interior surface of the side wall, extending intothe sleeve interior.

In some embodiments, the sleeve body and the core that extends into thesleeve interior are each formed of a gas-permeable refractory material.At least the core will comprise material selected for generating heatwhen heated by a molten metal.

In many of the embodiments, the core extends along the side wall of thesleeve body from the first end to a second end thereof. Such a core willhave a width that is constant or decreases in a radial direction awayfrom the side wall. Such a decreasing width is provided by a core thathas a triangular profile, with a base thereof in contact with the sidewall.

In many embodiments, the sleeve body is frustoconical, with a diameterthat decreases from the open first end to a second end thereof. Thesecond end of the sleeve body may be open or closed. In case where it isopen, it may be closable with a cover, sized and adapted to close thesleeve body at a second end thereof. In some cases, the cover may beformed integrally with the sleeve body at the second end.

The cover, when provided, may be provided with at least one aperturetherethrough. Such a cover would comprise a gas-permeable refractorymaterial and, optionally, material selected for generating heat whenheated by a molten metal. Preferably, these would be the same materialsas the sleeve body and core.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the disclosed embodiments will be obtainedfrom a reading of the following detailed description and theaccompanying drawings wherein identical reference characters refer toidentical parts and in which:

FIG. 1 is a side sectional view of a blind feeder sleeve with a Williamscore, as known in the prior art;

FIG. 2 is a side sectional view of an exemplary embodiment of a sleevehaving a Williams core, arranged in the same manner as the FIG. 1sleeve; and

FIG. 3 is a perspective view of a section of the FIG. 2 embodimentsleeve, rotated to show the sleeve with a longitudinal axis arrangedhorizontally.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows a side-sectional view of a typical blind feeder sleeve 10with a Williams core 12, in the manner generally taught by Trinkl in theprior art. This sleeve 10 has the Williams core 12 integrally formed asa part of the cover 14. The sleeve 10 has a longitudinal axis A, with aside wall 16 that is preferably symmetrical about the axis. In thedepicted embodiment, the side wall 16 appears to be somewhatfrustoconical, with the larger diameter at the open lower end 18.However, it would also be known to provide a cylindrical sidewall 16.The blind feeder sleeve 10 is arranged with the axis A aligned in avertical direction, facilitating outflow through open lower end 18 ofthe molten metal contained therein. Although not shown in FIG. 1, itwould be known to provide one or more vent apertures through cover 14 toenhance the gas-permeability of the material comprising the sleeve 10.

If the FIG. 1 embodiment 10 were to be placed in a mold with the axis Aaligned in a horizontal manner (rather than the illustrated verticalmanner), the beneficial effect of the Williams core 12 would be lost.

FIG. 2 shows, in side-sectional view, an embodiment that incorporatesthe concept of a Williams core for a feeder sleeve 110 that can be usedwith effect in a horizontal position. The sleeve 110 has a cover 114 anda side wall 116. As in the prior art example provided in FIG. 1, andsubject to an exception required by the Williams core that will bedescribed, the side wall 116 is designed for symmetry about alongitudinal axis. In this case, the axis is designated as B. Tofacilitate comparison with the prior art, the sleeve 110 in FIG. 2 isshown in the same orientation as the FIG. 1 sleeve. It can thus be seenthat the side wall 116 can have a frustoconical or cylindrical design.The cover 114, which is needed in the prior art to provide a base forthe Williams core, is not needed for that purpose in the FIG. 2 sleeve116. Opposite the cover 114 is an open end 118, which is substantiallythe same as the open lower end 18 of the FIG. 1 prior art. The cover 114can be either formed integrally with the sidewall 116 or it can beseparately formed in a size to fit into an otherwise open second end ofthe sleeve 110.

While continuing to consider FIG. 2, FIG. 3 is now introduced as asection view of the FIG. 2 embodiment 110 that allows a view down thelongitudinal axis B. In these views, it is readily seen that a portion120 of the side wall 116 has been formed to project in a radialdirection into the interior of the sleeve 110. As shown, the portion 120extends in the longitudinal direction essentially from the cover 114 tothe open end 118. In the depicted embodiment, the portion 120 is shapedas a wedge, with the larger base of the wedge formed along the side wall116. The portion 120 need not be a wedge, but it is preferred for theportion to have a constant profile along the entire length that extendsfrom the cover 114 to the open end 118. The portion 120 also does notneed to decrease in width in the manner shown in FIGS. 2 and 3, but itis preferred that the width does not increase as one moves from the sidewall towards the longitudinal axis.

When the portion 120 that exemplifies the features of a Williams core isintegrally formed during manufacture of the sleeve 110, it will haveessentially the same properties of gas-permeability, exothermicity, etc.as that provided by the side wall 116 of the sleeve. However, theprojection of the portion 120 into the interior space defined by theside wall 116 provides the improvement over a sleeve lacking theWilliams core structure.

As also seen in FIGS. 2 and 3, the cover may be provided with one ormore vent apertures 122. In the embodiment of FIGS. 2 and 3, there aretwo vent apertures 122 provided and they are placed near the portion120.

When placed into a sand mold where the longitudinal axis needs to bearranged horizontally, the preferred orientation for the embodiment 110is shown in FIG. 3. In this situation, the portion 120 is positioned atthe “top” or “12 o'clock” position, so that it is gravitationally abovethe molten metal reservoir formed in the sleeve 110 by the pour.

What is claimed is:
 1. A sleeve for use in metal casting, comprising: asleeve body having a longitudinal axis around which is formed a sidewall that defines an interior of the sleeve, the sleeve body being openat a first end thereof; and a core, formed integrally along an interiorsurface of the side wall and extending into the sleeve interior.
 2. Thesleeve of claim 1, wherein: the sleeve body and the core that extendsinto the sleeve interior are each formed of a gas-permeable refractorymaterial.
 3. The sleeve of claim 2, wherein: at least the core comprisesmaterial selected for generating heat when heated by a molten metal. 4.The sleeve of claim 1, wherein: the core extends along the side wall ofthe sleeve body from the first end to a second end thereof.
 5. Thesleeve of one of claim 1, wherein: the core has a width that is constantor decreases in a radial direction away from the side wall.
 6. Thesleeve of claim 5, wherein: the core has a triangular profile, with abase thereof in contact with the side wall.
 7. The sleeve of claim 1,wherein: the sleeve body is frustoconical, with a diameter thatdecreases from the open first end to a second end thereof.
 8. The sleeveof claim 1, further comprising: a cover, sized and adapted to close thesleeve body at a second end thereof.
 9. The sleeve of claim 1, furthercomprising, a cover, formed integrally with the sleeve body at a secondend thereof.
 10. The sleeve of claim 9, wherein: the cover is providedwith at least one aperture therethrough.
 11. The sleeve of claim 9,wherein: the cover comprises a gas-permeable refractory material and,optionally, material selected for generating heat when heated by amolten metal.
 12. The sleeve of claim 8, wherein: the cover is providedwith at least one aperture therethrough.
 13. The sleeve of claim 8,wherein: the cover comprises a gas-permeable refractory material and,optionally, material selected for generating heat when heated by amolten metal.
 14. The sleeve of claim 3, wherein: the core extends alongthe side wall of the sleeve body from the first end to a second endthereof.
 15. The sleeve of claim 3, wherein: the core has a width thatis constant or decreases in a radial direction away from the side wall.16. The sleeve of claim 15, wherein: the core has a triangular profile,with a base thereof in contact with the side wall.
 17. The sleeve ofclaim 3, wherein: the sleeve body is frustoconical, with a diameter thatdecreases from the open first end to a second end thereof.
 18. A sleevefor use in metal casting, comprising: a sleeve body having alongitudinal axis around which is formed a side wall that defines aninterior of the sleeve, the sleeve body being frustoconical, with adiameter that decreases from an open first end to a second end thereof;and a core, formed integrally along an interior surface of the side walland extending into the sleeve interior, the core having a triangularprofile, with a base thereof in contact with the side wall wherein eachof the sleeve body and the core are formed of a gas-permeable refractorymaterial, with at least the core further comprising material selectedfor generating heat when heated by a molten metal.
 19. A method ofpreparing a mold for casting a molten metal, comprising the steps of:providing a sleeve according to claim 1; providing a vertically-splitmold; inserting the sleeve in a first part of the vertically-split mold,such that an axis of the sleeve lies horizontally in the mold when themold is oriented to receive the molten metal, with the core of thesleeve positioned to be gravitationally above a reservoir of the moltenmetal reservoir formed in the sleeve by a pour of the molten metal.